[personal|tech] Having issues

My apologies for the relatively light link salad today, as well as the lack of any more substantial post. Chemo brain seems to have infected my MacBook Pro, and I’ve spent most of my blogging time this morning dealing with rebooting to clear a virtual memory issue that seems to be able to persist even through a shut down cycle.

I’ve actually been wrestling with this for a while. It’s a subtle error, and only appears on occasion, so my trip to the Genius Bar a while back was pretty much a waste. But when the error does appear, TextPad stops being able to save, which screws up my blog post build. Restarting TextPad doesn’t help at that point. If I don’t reboot then, eventually I get a system error that the startup disk is out of space for virtual memory. Mind you, this is a disk with 100GB available. At that point, there’s nothing for it but to Force Quit any open applications and reboot. And the Mac’s attempt to save my working state means that sometimes I come back from the reboot with the error still in play. Which requires yet another reboot.

So far, attempted fixes include replacing the hard drive in case of a bad sector, upgrading to Lion in case of an oddball system incompatibility in the previous OS release, and swapping Web browsers, twice. The problem still comes back, on an apparently random basis. This morning’s outbreak was by far the worst yet.

Of course, here’s me in late stage chemo, when I am not at my troubleshooting best. It’s entirely possible this is some obscure form of user error. But I can’t replicate it, and because I can’t replicate it, I can’t even do the requisite troubleshooting to pin down the offending application(s) or Web sites. Meanwhile, I’ve been considering buying a MacBook Air, and I’m now wondering if going to all new hardware will allow me to simply walk away from the issue.

All of which is a very long-winded way of apologizing for the dearth of new content today. I lose enough quality blogging days to chemo brain. It’s frustrating to lose one to tech wonkery.

My Macbook pro also developed an intermittent and difficult-to-replicate-for-the-genius-bar error, sadly enough coming to a head on the day Steve Jobs died, but since I was out of Apple Care, I chose instead to apply the funds to a new Air (and the gigantic Thunderbolt monitor, for when 13″ just isn’t enough).

L-O-V-E it!

And, noodling around with shiny new Apple products is always at least somewhat cheering … a little retail therapy?

Welcome to the world of stack overflows. This has little, or nothing, to do with the amount of space left on your hard disk. It has everything to do with the amount of space left in the rather small, hard-coded stack of memory used to point to temporary files on your hard disk.

Unfortunately, *nix-based operating systems — which includes OS X — have a variety of bugs built into their implementation of a flawed architecture based on the physical characteristics of superminicomputers built in 1972. What is supposed to happen is that the stack is supposed to dynamically rearrange itself, purge unused segments, and consolidate them so that there’s always a relatively large contiguous segment of stack. In reality, not so much… because if the OS is doing ANYTHING related to disk access at the time that it’s supposed to be doing this housekeeping, it instead does nothing (to protect the integrity of the disk). Since modern multimedia systems have a lot more going on than the systems for which this architecture were developed did, too often the stack cleanup doesn’t get done. Then, when it’s time to write a temporary file or backup file (by reputation, particularly anything related to Time Machine), there isn’t a big enough free segment on the stack… which looks, to the operating system, like there’s no virtual memory.

OK, after that explanation, is there a solution? I’m not sure; I don’t use toys from Cupertino. (Real computers have ferrite core memory and punchcard input, you young whippersnappers.) I suspect that the best way to handle this is to do a controlled shutdown fairly frequently, which is the only guaranteed way to reset a *nix stack. One other workaround might be to just shut down all multimedia programs well before sending the computer to sleep for the evening. That is, the worst thing you could do at the end of a day is let it watch TV right up until bedtime!

I also strongly suspect that there are “it’s not a bug, it’s a feature” aspects of Time Machine and your well-documented concern* with constanting backing up your data. That, however, I’ll leave to someone who understands more about the particular *nix implementation sitting under OS X.

* It’s not paranoia if the computer failure demons really are out to get you… and they are.

Consult an expert who’s thoroughly at home with _current_ OS X technology. I am very positive that your problem can be solved. Start the activity monitor whenever you start your session and leave it running all the time. Have a look at it every now and then and try to get a feel for how much memory the individual processes usually take up. Take notes of unusual activities or peaks, or save screenshots of the activity monitor and show them to the expert later. Perhaps it’s a single application that causes your troubles. In that case, new hardware wouldn’t help.